Sheet side guiding device, sheet feeding device and image forming apparatus

ABSTRACT

The sheet side guiding device includes a tray on which sheets are placed, a side guide provided on the tray to be slidable in a direction normal to the feeding direction of the sheet and configured to guide side portions of the sheets to be fed, a rubber sheet provided on the tray in the sliding direction of the side guide, a lever provided pivotably on the side guide via a pivot mechanism and an engagement stopper nail portion provided for the end portion of the lever and configured to detachably engage with the rubber sheet to lock the side guide to the tray.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2003-307431, filed Aug. 29, 2003,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet side guiding device placed on atray, which guides sheets of an original or copy sheets fed from thetray, to suit the lateral sides of the sheets in their width direction,as well as a sheet feeding device and an image forming apparatus.

2. Description of the Related Art

Image forming apparatus such as a copy machine, scanner and facsimileinclude a tray on which originals, copy sheets, or the like etc. areplaced. The sheets placed on the tray are fed one by one to an imageformation processing unit of an image forming apparatus in accordancewith a sheet feeding signal, where an image is formed on a sheet.

The tray is equipped with a guiding device for suiting the side edges ofthe sheets placed thereon in order to feed them to the image formationprocessing unit in a proper position. The sheets have various sizes suchas B5, A4 and A3. The guiding device is designed to guide sheets bytheir side edges in accordance with the width dimension of the sheets.

Jpn. Pat. Appln. KOKAI Publication No. 11-79418 discloses a sheet sideguiding device and a technique of an image processing apparatus thatuses this guiding device. In the guiding device, a rack-shapedengagement sections are provided on the surface side of a tray along thelongitudinal direction of grooves formed in the tray, and engagementcontrol units are provided for side guides that are slidable along thelongitudinal direction of the grooves. The engagement control units areprovided with engagement nails that detachably engage with theengagement units.

It should be noted that the above-described techniques employs a rachetstructure in which the displacement of the side guides is controlled asthe engagement nails engage with the engagement units. If an externalforce is applied to the side guides in a direction that opens the sideguides (that is, a direction in which the side guides move away from theside edges of sheets placed on the tray), the displacement of the sideguides can be controlled.

The rachet structure includes rachet teeth provided at a predeterminedpitch and bottoms each formed between adjacent rachet teeth, and theengagement nails engage with the bottoms each formed between theadjacent teeth.

For the convenience of the manufacturing of parts, it is usuallynecessary to ensure about 0.5 to 0.7 mm for the pitch of the rachetteeth. If an engagement nail is locating at a position opposite to arachet tooth, the position of the engagement nail must be displaced. Inother words, the engagement position of the engagement tooth iscontrolled with reference to the pitch of the rachet teeth, and thepositions of the side guides can be locked only in units of pitch.

Some types of the sheet side guiding device are designed to guide oneside of sheets with a fixed side guide and the other side edge with aslide-adjustable side guide to fit the size of the sheets. Other typesare designed to guide both sides of sheets with slide-adjustable sideguides to fit the width of the sheets with reference to the centerposition of the sheets in their width direction.

In the case of the former type of the guiding device, the engagementposition displaces in units of the pitch of the rachet teeth. In thecase of the latter type, the side guides on both sides are usuallycoupled to each other by a rack and pinion to move symmetrically, andtherefore the engagement position displaces in units of a double of thepitch of the rachet.

In both types of the guiding device, it is difficult to position and fixthe side guides to fit perfectly with side edges of sheets of varioussizes.

BRIEF SUMMARY OF THE INVENTION

The present invention has been proposed in consideration of theabove-described circumstances, and the object thereof is to provide asheet side guiding device that can position and fix the side guides in astepless manner, as well as a sheet feeding device and an image formingapparatus.

According to an aspect of the present invention, there is provided asheet side guiding device comprising: a tray on which sheets are placed;a guide member, provided on the tray to be slidable in a directionnormal to a sheet feeding direction, configured to guide side portionsof the sheets to be fed; an elastic member provided on the tray in asliding direction of the guide member; a lever provided pivotably on theguide member via a pivot mechanism; and an engagement stopper nailportion, provided for an pivot end portion of the lever, configured todetachably engage with the elastic member to lock the guide member tothe tray.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be leaned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a diagram schematically showing the structure of a digitalcopying machine according to an embodiment of the present invention;

FIG. 2 is a perspective view of a tray equipped with a sheet sideguiding device;

FIG. 3 is an exploded perspective view of the sheet side guiding device;

FIG. 4 is a cross sectional view of portions of the first side guide andlever;

FIG. 5 is a cross sectional view of the first side guide and lever;

FIG. 6 is a diagram showing the relationship between a force applied tothe lever and the operation of an engagement stopper nail portion;

FIG. 7 is a diagram showing the state in which the engagement stoppernail portion is brought into contact with a rubber sheet;

FIG. 8 is a diagram showing the relationship between a force applied tothe lever and the operation of an engagement stopper nail portion in acomparative example;

FIG. 9 is a diagram showing the state in which the engagement stoppernail portion is brought into contact with a rubber sheet in thecomparative example shown in FIG. 8; and

FIG. 10 is a diagram showing a cross section of the first side guideaccording to the embodiment of the present invention when viewed from afront direction.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will now be described in detailwith reference to accompanying drawings.

FIG. 1 shows the entire structure of a digital copying machine F, whichis an image forming apparatus equipped with a manual sheet feedingdevice S, according to an embodiment of the present invention.

The digital copying machine F comprises a main body 100, and an originaltray 101 on which originals are placed one by one is provided on anupper surface portion of the main body 100. An automatic originalfeeding unit 102 that automatically feeds originals onto the originaltray 101 is provided on the original tray 101.

An image reading unit (scanner) 103 that reads an image of an originalplaced on the original tray 101 is provided underneath the original tray101. An image forming unit 104 that forms an image of an original readby the image reading unit 103 is provided underneath the image readingunit (scanner) 103. A sheet feeding unit 112 is provided underneath theimage forming unit 104. The sheet feeding unit 112 includes sheetfeeding cassettes 113 and 114.

In the meantime, a manual sheet feeding unit S is provided at a lowersection of a lateral surface of the main body 100. The manual sheetfeeding unit S is provided with a sheet side guiding device that guidessides of sheets in the width direction for various sizes of sheets aswill be described in detail later.

A sheet fed from the sheet feeding cassette 113 or 114, or the manualsheet feeding unit S is conveyed to the image forming unit 104, where animage is formed on the sheet.

FIG. 2 is a perspective view showing the manual sheet feeding unit S.

The manual sheet feeding unit S includes a tray 130. A sheet P is placedon the tray 130 and the sheet is fed in a direction indicated by thearrow. The tray 130 is provided with a guide device that guides bothside of the sheet P that has been fed thereto.

The tray 130 includes a table plate 1 and first and second supportplates 3A and 3B are formed to be integrated with the table plate 1. Afirst side guide 10 and a second side guide 20 that form the guidingdevice are movably supported on the support plates 3A and 3B,respectively. The first and second side guides 10 and 20 move indirections that are normal to the sheet feeding direction.

The support plates 3A and 3B each have a guide groove portion 2 a usedto guide the movement of the side guides 10 and 20. The guide grooveportions 2 a are through holes made in the plates over respectiveregions where the side guides 10 and 20 are movable respectively.

The first side guide 10 is movably fit into the guide groove portion 2 aof the first support plate 3A and the second side guide 20 is movablyfit into the guide groove portion 2 a of the second support plate 3B.Each of the first and second side guides 10 and 20 is formed to havesubstantially an L shape, which is formed of a bottom plate portion 5and a guide wall 6 standing straight up from one side end of the bottomplate portion 5.

A lever 15 is provided for the guide wall 6 of the first side guide 10.A rubber sheet 7, which is an elastic member used for registration, ismounted on the first support plate 3A along the moving direction of thefirst side guide 10. A lower end surface of the lever 15 is brought intocontact with the rubber sheet 7 to be opposite thereto. An example ofthe material of the rubber sheet 7 is a CR rubber member having ahardness of 45 to 60 degrees. The surface of the rubber sheet 7 isclosely grained and is made substantially plane. The level 15 is formedof a synthetic resin material such as plastic, and its hardness is setto be higher than that of the rubber sheet 7.

FIG. 3 is a perspective view showing the interlocking mechanism betweenthe first and second side guides 10 and 20.

The interlocking mechanism includes first and second racks 11 and 12placed in parallel with and face each other. The first rack 11 is fixedto the bottom plate portion 5 of the first side guide 10 with a screw300. The second rack 12 is fixed to the bottom plate portion 5 of thesecond side guide 20 with a screw 300. Each screw 300 is pierced throughto the respective guide groove portion 2 a. A pinion gear 13 isinterposed between the first and second racks 11 and 12 to engage withthese racks.

With this structure, when the first side guide 10 is moved to, forexample, the right in the illustration shown in FIG. 3, the first rack11 is moved in the same direction to rotate the pinion gear 13 in aclockwise direction. Then, as the pinion gear 13 rotates, the secondrack 12 is moved. Due to the movement of the second rack 12, the secondside guide 20 is moved to the left in the illustration shown in FIG. 3.In other words, the first and second side guides 10 and 20 are moved inthe respective directions that they become closer to each other each bythe same moving amount.

On the other hand, when the first side guide 10 is moved to, forexample, the left in the illustration shown in FIG. 3, the first rack 11is moved in the same direction to rotate the pinion gear 13 in acounter-clockwise direction. Then, as the pinion gear 13 rotates, thesecond rack 12 is moved. Due to the movement of the second rack 12, thesecond side guide 20 is moved to the right in the illustration shown inFIG. 3. In other words, the first and second side guides 10 and 20 aremoved in the respective directions that they become apart from eachother each by the same amount. In the above-described manner, the firstand second side guides 10 and 20 are moved in the respective directionsthat they part from each other with respect to the pinion gear 13 at thecenter.

FIGS. 4 and 5 are cross sectional views of an installation structure ofthe lever 15 to the first side guide 10.

The lever 15 is mounted pivotably via a pivot mechanism 30 to a lowerportion of the guide wall 6 of the first side guide 10. The upper endportion of the lever 15 is a free end and the lever is pivoted on apivot P with respect to the first side guide 10.

A plate spring (elastic member) 17 is interposed between the first sideguide 10 and the lever 15. The plate spring 17 is formed to havesubstantially a U shape. A half portion of the plate spring 17 is set inprojecting portions 15 a formed on an inner surface of the lever 15while being fit with these portions, and an end portion of the otherhalf portion is set to abut against a protruding portion 18 formed onthe wall surface of the first side guide 10. In other words, the platespring 17 serves to elastically urge the lever 15 to pivot in thecounter-clockwise direction on the pivot P.

A lower end surface portion of the lever 15 has an engagement stoppernail portion 31 formed thereon as shown in FIG. 5. The lever 15 and theengagement stopper nail portion 31 form an engagement portion 35together.

The engagement stopper nail portion 31 digs into the rubber sheet 7 onthe first support plate 3A so as to fixate the lever 15 and the firstside guide 10.

It should be noted that the engagement stopper nail portion 31 digginginto the rubber sheet 7 means, in this embodiment, a state in which thesurface of the rubber sheet 7 is deformed to depress by the engagementstopper nail portion 31. Therefore, when the engagement stopper nailportion 31 is released from the rubber sheet 7, the rubber sheet 7restores its original state by the elastic force of itself.

A stopper portion 32 that projects towards the lever 15 is formedintegrally at a lower end portion of the guide wall 6 of the first sideguide 10. Before the first side guide 10 is set on the support plate 3A,the stopper portion 32 serves to regulate the pivoting amount of thelever 15, which is pivoted by the elastic force of the spring plate 17,by making the end portion the lever abut against the stopper portion 32.When the first side guide 10 is set on the support plate 3A, theengagement stopper nail portion 31 of the lever 15 digs into the rubbersheet 7, thus creating a certain gap a between the lever 15 and stopper32.

It should be noted here that the rubber sheet 7 may be damaged if theengagement stopper nail portion 31 digs in excessively for a hardness ofthe rubber sheet 7. In order to avoid this, the digging amount of thenail portion is adjusted by the stopper portion 32.

FIGS. 6 and 7 are schematic diagrams showing the stopper nail portion 31provided on the lever 15 and the pivot P to illustrate how they arerelated with each other in terms of position.

When conveying a sheet while guiding the side edges of the sheet withthe first and second side guides 10 and 20, the sheet in some casesskews. When the sheet skews, the side guides 10 and 20 receives a forceF in the direction that each guide is expanded outwards. At normaltimes, the lever 15 is urged by the plate spring 17 and therefore theengagement stopper nail portion 31 is held in a state in which it ispressed against the rubber sheet 7. In this state, when the force Freceived by the side guide 10 is applied to the lever 15 via the pivotP, a counter-clockwise rotation moment Ma acts on the lever 15 in adirection in which the engagement stopper nail portion 31 further digsin the rubber sheet 7.

As shown in FIG. 7, the lever 15 is inclined in the direction of therotation moment Ma, and it is directed to the direction in which theengagement stopper nail portion 31 can easily dig in the rubber sheet 7used for positioning. In other words, when the first side guide 10receives the force in the direction in which the guide 10 is expandedoutwards, the stopper nail portion 31 of the lever 15 serves as aresistant to the positioning rubber sheet 7 so as to regulate thedisplacement of the first side guide 10 as well as the second side guide20.

FIGS. 8 and 9 are perspective views of a comparative example to theabove-described embodiment of the present invention, which illustratesthe positions of the engagement stopper nail portion 31A of the lever15A and the pivot P with relative to each other.

This comparative example is different from the above-describedembodiment in the point that the engagement stopper nail portion 31A isformed to be directed in an opposite direction to that of the stoppernail portion 31 shown in FIG. 6. This comparative example is the same asthe embodiment in the position of the pivot P and the other structurethan the described point.

As shown in FIG. 8, when sheets are set to abut against the first sideguide 10 and a force F is applied to the first side guide 10 in adirection in which the guide 10 is expanded outwards, a rotation momentMa directed in a counter-clockwise direction with respect to the pivot Pacts on the lever 15A.

Consequently, the lever 15A is inclined in the direction of the rotationmoment Ma. However, with the structure in which the engagement stoppernail portion 31A is formed to be directed in the opposite direction tothat of the stopper nail portion 31 shown in FIG. 6, there acts lessresistance on the positioning rubber sheet 7. As a result, the firstside guide 10 and the second side guide 2 are easily displaced.

FIG. 10 is a cross sectional view showing the structure in which thefirst side guide 10 is installed on the first support plate 3A, whenviewed from a front direction.

The first support plate 3A is provided with a plurality of guide grooveportions 2 a in which the first side guide 10 is slidably supported, asexplained before.

A press piece portion 10 b is integrated with an end of the first sideguide 10, and the press piece portion 10 b is inserted to the guidegroove portion 2 c and bent in the horizontal direction to be broughtinto contact with the rear surface of the surface plate 1.

When the engagement stopper nail portion 31 of the lever 15 of the firstside guide 10 is stopped by the positioning rubber sheet 7 serving as apositioning elastic member, the nail portion receives an elasticrepulsion force. The force acts on the first support plate 3A of thefirst side guide 10 to float together with the lever 15.

However, as it is, there is a gap created between the lower end of thefirst side guide 10 and the first support plate 3A, which is notdesirable in terms of appearance, and the smooth sliding of the firstside guide 10 is impaired.

In order to avoid this, the press piece portion 10 b is formed to beintegrated with an end portion of the first side guide 10 as describedabove, thereby inhibiting the floating up of the first side guide 10.

In this manner, there is no gap created between the lower end of thefirst side guide 10 and the first support plate 3A, thereby making itpossible to maintain its good appearance and retain the smooth slidingof the first side guide 10.

Next, the operation of the sheet side guiding device having theabove-described structure will now be described.

First, as shown in FIG. 2, sheets P are placed between the first andsecond side guides 10 and 20 on the tray 130. When there is a gapbetween the sheets P and one or both of the first and second side guides10 and 20, the upper end portion of the lever 15 of the first side guide10 is fingered to pivot the lever 15 on the pivot P in the clockwisedirection. In this manner, the stopper nail portion 31 of the lever 15is removed from the rubber sheet 7, thereby releasing the lock. Afterreleasing the lock, the first side guide 10 is slid to fit with thewidth of the sheets. Due to this adjustment, the second side guide 20 ismoved at the same time by the same amount. Then, when both of the firstand second side guides 10 and 20 reach the respective side edges of thesheets, the lever 15 is released from the finger. In this manner, thelever 15 is pivoted back in the counter-clockwise direction by theelastic force of the plate spring 17 to return to the original position.Thus, the engagement stopper nail portion 31 digs in the rubber sheet 7as shown in FIG. 6, thereby fixating the lever 15 and the first sideguide 10. Further, as the first side guide 10 is fixated, the secondside guide 20 is fixated as well by means of the first and second racks11 and 12.

As described above, according to this embodiment, the engagement stoppernail portion 31 of the lever 15 is made to dig in the rubber sheet 7 tofixate the lever 15. With this structure, it is possible to position andfixate the first and second side guides 10 and 20 in a stepless manner.

Therefore, as compared to the conventional rachet structure, in whichthe guides can only be positioned and fixated in a stepwise manner, thefirst and second side guides 10 and 20 can be fixated while setting themto perfectly fit with the respective side edges of the sheets.

Further, the engagement stopper nail portion 31 is formed to be directedin a direction that the nails dig into the rubber sheet 7 against theforce serving to outwardly expand the first and second side guides 10and 20. Thus, the first and second side guides 10 and 20 are notdisplaced along with the lever 15, and they can be maintained certainlyat predetermined positions respectively.

It should be noted that the above-described embodiment has such astructure that the first and second side guides 10 and 20 are slid inopposite directions from each other by the same amount as shown in FIG.3; however the invention is not limited to this structure, but it cantake a structure, for example, that one of the side guides is fixatedand only the other one is formed to be slidable. In this case,naturally, the lever 15 is provided for the slidable side guide.

Further, in the above-described embodiment, the lever 15 is formed as aseparate member from the first side guide 10; however it is possiblethat the lever function can be equipped in a part of the side guide 10itself. In other words, in this alternative version, an engagementstopper nail portion is provided for the lower end portion of the sideguide 10 and an urging force to make the stopper nail portion to diginto the positioning rubber sheet 7 is applied at all times. Then, theengagement stopper nail portion is released from the positioning rubbersheet 7 as needed, for example, when sliding the side guide 10.

It is alternatively possible to take such a structure that the lever 15,pivot mechanism 30 and plate spring 17 are formed to be integrated withthe first side guide 10.

Further, in the above-described embodiment, the lever 15 is provided ata longitudinal center of the first side guide 10; however the lever 15may be provided on either one of the longitudinal end portions of thefirst side guide 10.

Furthermore, the engagement stopper nail portion 31 may be formed longerin the longitudinal direction of the rubber sheet 7.

In the embodiment, the sheet-like rubber material is used as thepositioning elastic member 7; however it is alternatively possible touse a thick block-like rubber material.

Further, in the embodiment, the sheet side guiding device S is providedfor the tray 130, which is a manual sheet feeding unit. However, thepresent invention is not limited to this structure, but the guidingdevice S may be provided for the above-described automatic originalsheet feeding unit 102 or within the sheet feeding cassettes 113 and 114in the feeding unit 112.

Further, in the embodiment, the sheet side guiding device is used forthe digital copying machine F; however the guiding device may be usedfor ordinary analog-mode copying machines. In fact, the presentinvention can be applied to all types of image forming apparatusincluding scanners and facsimiles.

Further, the present invention is not limited to the above-describedembodiment, but naturally it can be modified into various versionswithin such a scope where the essence of the invention remains.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A sheet side guiding device comprising: a tray on which sheets areplaced; a guide member provided on the tray to be slidable in adirection normal to a sheet feeding direction and configured to guideside portions of the sheets to be fed; an elastic member provided on thetray along a sliding direction of the guide member; a lever providedpivotably on the guide member via a pivot mechanism; and a nail portionprovided for an end portion of the lever and configured to detachablyengage with the elastic member.
 2. The sheet side guiding deviceaccording to claim 1, wherein a surface of the elastic member, withwhich the nail portion engages, is made substantially plane.
 3. Thesheet side guiding device according to claim 1, wherein the guide membercomprises a regulating portion configured to regulate floating-up of theguide member from the tray.
 4. The sheet side guiding device accordingto claim 1, wherein the lever is elastically urged by an urging memberin a direction in which the end portion of the lever abuts against theguide member, and the guide member includes a stopper portion thatreceives the end portion of the lever urged.
 5. The sheet side guidingdevice according to claim 1, wherein a pivot of the pivot mechanism thatsupports the lever rotatably is provided at a position where the nailportion resists against the elastic member while the guide memberreceives a force in a direction in which the guide member moves awayfrom a side edge of the sheets to incline the lever.
 6. The sheet sideguiding device according to claim 5, wherein the nail portion points ina direction in which the engagement stopper nail portion serves toresist against the elastic member while the guide member receives aforce in a direction in which the guide member moves away from a sideedge of the sheets to incline the lever.
 7. The sheet side guidingdevice according to claim 1, wherein the elastic member is a rubbersheet.
 8. The sheet side guiding device according to claim 1, whereinthe lever is formed of a synthetic resin material.
 9. The sheet sideguiding device according to claim 1, wherein the nail portion is harderthan the rubber sheet.
 10. The sheet side guiding device according toclaim 1, wherein the guide member includes first and second side guidesthat guide respective sides of the sheets, and the first and second sideguides are movable in directions in which the side guides move away fromthe sides of the sheets by a same amount.
 11. The sheet side guidingdevice according to claim 1, wherein the lever is integrated with theguide member.
 12. The sheet side guiding device according to claim 1,wherein the lever is provided at substantially a central portion of theguide member in the paper feeding direction.
 13. A sheet feeding devicecomprising: a tray on which sheets are placed; a sheet feeder configuredto feed the sheets placed on the tray to a sheet receiving portion; aguide member provided on the tray to be slidable in a direction normalto a sheet feeding direction and configured to guide side portions ofthe sheets to be fed; an elastic member provided on the tray in asliding direction of the guide member; a lever provided pivotably on theguide member via a pivot mechanism; and a nail portion provided for anend portion of the lever and configured to detachably engage with theelastic member.
 14. An image forming apparatus comprising: a tray onwhich sheets are placed; a sheet feeder configured to feed the sheetsplaced on the tray; an image forming unit configured to form an image ona sheet fed by the sheet feeder; a guide member provided on the tray tobe slidable in a direction normal to a sheet feeding direction andconfigured to guide side portions of the sheets to be fed; an elasticmember provided on the tray in a sliding direction of the guide member;a lever provided pivotably on the guide member via a pivot mechanism;and a nail portion provided for an end portion of the lever andconfigured to detachably engage with the elastic member.